Cementing Stage Collar with Dissolvable elements

ABSTRACT

A cementing stage collar and a method. The cementing stage collar may include dissolvable parts.

This application claims priority from U.S. provisional patent Ser. No.62/502961 filing date May 8, 2017.

BACKGROUND

A hydraulic, ball or cement plug-actuated cementing stage collarsprovide effective isolation for specifically targeted, annular sectionsof a wellbore when the standard method of placing cement from the bottomof the well depth to the surface exerts greater hydrostatic pressurethan what the targeted formation can tolerate. Typically, a well designwhere the formation to be stimulated requires to be open hole, acementing stage collar can facilitate cementing of a production casingstring while leaving the open hole section undisturbed. FIG. 1illustrates a cement stage collar 100 that is used to provide cement 14to a certain segments of a wellbore. The cement 14 is delimited by linerhangers 12. A debris sub 110 is positioned downstream to the linerhangers 12 and prevents the progress of debris downstream towards a fracsleeve 22. Open hole packers are used to segment an open hole 24.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter regarded as the invention is particularly pointed outand distinctly claimed in the concluding portion of the specification.The invention, however, both as to organization and method of operation,together with objects, features, and advantages thereof, may best beunderstood by reference to the following detailed description when readwith the accompanying drawings in which:

FIG. 1 illustrates an example of a well;

FIG. 2 is an example of a cementing stage tool before drill out;

FIG. 3 is an example of cementing stage tool after drill out;

FIG. 4 illustrates various examples of various parameters of dissolvablematerials;

FIG. 5 is an example of a protective coating;

FIG. 6 is an example of a cementing stage tool;

FIG. 7 is an example of a cementing stage tool;

FIG. 8 is an example of a cementing stage tool;

FIG. 9 is an example of a cementing stage tool;

FIG. 10 is an example of a cementing stage tool;

FIG. 11 is an example of a cementing stage tool; and

FIG. 12 is an example of a cementing stage tool.

DETAILED DESCRIPTION OF THE DRAWINGS

In the following detailed description, numerous specific details are setforth in order to provide a thorough understanding of the invention.However, it will be understood by those skilled in the art that thepresent invention may be practiced without these specific details. Inother instances, well-known methods, procedures, and components have notbeen described in detail so as not to obscure the present invention.

It will be appreciated that for simplicity and clarity of illustration,elements shown in the figures have not necessarily been drawn to scale.For example, the dimensions of some of the elements may be exaggeratedrelative to other elements for clarity. Further, where consideredappropriate, reference numerals may be repeated among the figures toindicate corresponding or analogous elements.

Any reference in the specification to a system should be applied mutatismutandis to a method that can be executed by the system.

Because the illustrated embodiments of the present invention may for themost part, be implemented using mechanical components known to thoseskilled in the art, details will not be explained in any greater extentthan that considered necessary as illustrated above, for theunderstanding and appreciation of the underlying concepts of the presentinvention and in order not to obfuscate or distract from the teachingsof the present invention.

Most Cementing Stage Collars functions similarly in that Opening Sleeveis actuated by applied casing pressure acting on a differential pistonarea of the Opening Sleeve. In FIG. 2, a cementing stage collar 100 isillustrates as including a body 110 an opening sleeve 106, a closingsleeve 102 and a closing seat 104 that is configured to receive a ball120 thereby forming a seal for preventing the progress of cement.

The applied internal casing pressure shifts the Opening Sleeve down toexpose flow ports. Cement can then be pumped through these ports andinto the casing annulus. Upon the completion of the cement pumpingcycle, A Ball is pumped down to land on the Closing Seat. By applyingspecific casing pressure to the landed Ball, the Closing Seat andphysically coupled Closing Sleeve are shifted down. Ultimately, theClosing Sleeve seals off the flow ports to shutoff the pressurecommunication and flow to the annulus and locks into position such thatno inadvertent movement would occur that could reopen the ClosingSleeve.

After the cement has been injected into the annulus through theCementing Stage Collar, the Ball, Closing Seat and Opening Seat must beremoved from the well bore so that fluids can pass freely from thesurface to the entirety of the well bore.

The Closing Seat, Ball and Opening Sleeve are manufactured fromdrillable material, commonly cast iron or aluminum.

To remove the Ball, Closing Seat and Opening Seat, a milling tool, sizedaccording to the casing drift diameter or smaller, is lowered to the topof cement that remains above the Cementing Stage Collar. Using therotary capabilities of the Rig or a downhole motor, the milling tool ispressed against the remaining cement above the Cementing Stage Collarand is rotated such that the milling tool drills through the cement,Ball, Closing Seat, and Opening Sleeve of the Cementing Stage Collar.Once the ID of the Cement Stage Collar is fully open, subsequent workcan commence without having mechanical obstructions at the CementingStage Collar.

A common consequence of “drilling out” these components is that thin,cylindrical remnants (112 and 124 of FIG. 3) which are mechanicallyattached to the Closing Sleeve remain as the drill milling tool passesthrough.

Often due to the wobbling of the milling tool, these remaining remnantscan be irregularly shaped, even broken. In all cases these remnants canbe dislodged such that they can fall down through the wellbore duringpost-drill out operations. These remnants form debris that can and willinterfere with many precision equipment located below the CementingStage Collar. A typical solution to deal with the issue is to mount anadditional component in the casing string such as a Debris Sub below theCement Stage Collar to capture this debris. However, these Debris Subsultimately are drilled out as well leaving debris in the well bore.

The design of the Cementing Stage Collar can be clearly improved byusing dissolvable materials, instead of drillable materials, tomanufacture at least one of the Ball, Closing Seat, and Opening Seat—andespecially all of the Ball, Closing Seat, and Opening Seat. Whendissolvable materials are used for these Components, any debris thatremains in the wellbore will dissolve.

The Ball, Closing Seat, and Opening Seat can be made of the samedissolvable material (or materials) or may differ from each other bycomposition.

At least two out of the Ball, Closing Seat, and Opening Seat can be madeof the same dissolvable material (materials). At least two out of theBall, Closing Seat, and Opening Seat can be made of differentdissolvable materials.

The Ball, Closing Seat, and Opening Seat are non-limiting example ofdelimiting components.

Non-limiting examples of dissolvable materials that can be used forforming at least one of the Ball, Closing Seat, and Opening Seat areprovided below.

Any dissolvable material that can be compatible to oil and/or gaspumping operations can be used.

Any dissolvable material may be proprietary, or non- proprietary.

The dissolvable materials can be classified according to their majorconstituency.

Magnesium and aluminum-based alloys are most prominent.

Plastic based alloys may also be used.

The metallic materials are suitable for components of the CementingStage Collar given their machinability, hardness and strength.

The dissolvable materials me be designed to dissolve in any fluid-including but not limited to fluids commonly found in the well bore. Thesample charts below in FIG. 4 depict a diameter loss vs time (hours) ofdissolvable material in and temperature of fluids found in common wells.In FIG. 4 lines 181, 182, illustrates the fixed rates of 0.66 mm/hourand 0.55 mm/hour reduction—and curves 183 and 184 illustrates a ratevariable reduction in two test cases. It should be noted that there maybe a variety of dissolvable materials—all of which will dissolve atdifferent rates in different environments.

The KCl Brine, often used in the drill out and completions operationscan readily dissolve components made of dissolvable materials. As such,a non-dissolvable coating can be introduced to these components to stoppremature dissolution until after drilling out. See FIG. 5. The coatingmay be thin.

These coatings include, but are not exclusive to paints, epoxies,elastomers, plastics, and ceramics.

The unprotected surfaces exposed by drilling out the coating may startthe dissolving process and will predictively dissolve or degrade intosufficiently smaller pieces such that they will easily be transportedout of the casing with normal fluid circulation.

With a full dissolution of these dissolvable components, no remnantswill remain as debris to hinder downhole operations such as frackingwith ball-actuated Frac Sleeves, et al.

Using one or more dissolvable materials for forming at least two out ofthe Ball, Closing Seat, and Opening Seat provides a simple design, Nodebris to interfere with downhole tools; e.g., ball-actuated FracSleeves, Greater ID than drilled diameter at the Stage Collar afterdissolving to match casing ID., No need for Debris Sub and Reduced riskand cost.

There may be provided a method that may include (a) injecting cement oranother filling material within a space that is delimited by at leastone delimiting component out of Ball, Closing Seat, and Opening Seat,where at least one of the Ball, Closing Seat, and Opening Seat is madeof dissolvable material (materials), and (b) dissolving (preferablyafter the completion of step (a)) the at least one delimiting componentthat is made of the dissolvable material (materials).

FIGS. 6-12 illustrates a cementing stage collar 200.

The cementing stage collar 200 may include

-   -   a. Body 210 that includes one or more flow ports 220. For        simplicity of explanation it is assumed that there are multiple        flow ports. Cement may flow through the one or more flow ports        in order to fill an annulus. The flow ports may be arranged in        any manner—for example in a symmetrical or a non-symmetrical        manner, to form an annular array, and the like. The flow ports        may include sealing elements.    -   b. A group of sleeves. The group may include one or more        sleeves. FIGS. 7-10 illustrate a group of sleeves that includes        an opening sleeve 240 and a closing sleeve 230. The group of        sleeves includes an exit port. The group of sleeves is        configured to move within the body thereby selectively blocking        the flow ports and selectively exposing the flow port to an        interior 260 of the cementing stage collar. When exposed to the        flow port—cement that propagates through the interior flows        propagates through flow ports 220 to the annulus—while being        prevented (by stopper 250) to propagate via through port 262        downstream to the cementing stage collar.    -   c. A first closing element that is configured to receive a        sealing element (such as ball 120) and to seal the cementing        stage collar. The first closing element is dissolvable. The        first closing element may be a closing seat.

The closing seat may include removable and non-solvable cover (that canbe made of a protective coating such as protective coating 105 of FIG.3) that covers a dissolvable portion of the closing seat.

At least a part of the group of sleeves may be dissolvable. Forexample—the opening sleeve may include at least one dissolvable part,may be entirely made of dissolvable material, and the like.

The stopper 250 may be configured to seal a through port 262 of theinterior 260 thereby preventing fluid to exit downstream of the certaininternal sleeve when the flow port is exposed to the interior of thecertain sleeve. The stopper 250 can be made of dissolvable materials. Itcan include a removable and non-solvable cover.

The opening sleeve 240 may include a removable non-solvable cover thatcovers a dissolvable portion of the opening sleeve.

The closing sleeve 230 may be configured to selectively block the flowport. The opening sleeve 240 may be configured to electively expose theflow port to an interior of the opening sleeve.

In the foregoing specification, the invention has been described withreference to specific examples of embodiments of the invention. It will,however, be evident that various modifications and changes may be madetherein without departing from the broader spirit and scope of theinvention as set forth in the appended claims.

The terms “including”, “comprising”, “having”, “consisting” and“consisting essentially of” are used in an interchangeable manner. Forexample- any method may include at least the steps included in thefigures and/or in the specification, only the steps included in thefigures and/or the specification.

Moreover, the terms “front,” “back,” “rear” “top,” “bottom,” “over,”“under” and the like in the description and in the claims, if any, areused for descriptive purposes and not necessarily for describingpermanent relative positions. It is understood that the terms so usedare interchangeable under appropriate circumstances such that theembodiments of the invention described herein are, for example, capableof operation in other orientations than those illustrated or otherwisedescribed herein.

Those skilled in the art will recognize that the boundaries betweenvarious components are merely illustrative and that alternativeembodiments may merge various components or impose an alternatedecomposition of functionality upon various components. Thus, it is tobe understood that the architectures depicted herein are merelyexemplary, and that in fact many other architectures can be implementedwhich achieve the same functionality.

Any arrangement of components to achieve the same functionality iseffectively “associated” such that the desired functionality isachieved. Hence, any two components herein combined to achieve aparticular functionality can be seen as “associated with” Each othersuch that the desired functionality is achieved, irrespective ofarchitectures or intermedial components. Likewise, any two components soassociated can also be viewed as being “operably connected,” or“operably coupled,” to Each other to achieve the desired functionality.

Furthermore, those skilled in the art will recognize that boundariesbetween the above described operations merely illustrative. The multipleoperations may be combined into a single operation, a single operationmay be distributed in additional operations and operations may beexecuted at least partially overlapping in time. Moreover, alternativeembodiments may include multiple instances of a particular operation,and the order of operations may be altered in various other embodiments.

However, other modifications, variations and alternatives are alsopossible. The specifications and drawings are, accordingly, to beregarded in an illustrative rather than in a restrictive sense.

In the claims, any reference signs placed between parentheses shall notbe construed as limiting the claim. The word ‘comprising’ does notexclude the presence of other elements or steps than those listed in aclaim. Furthermore, the terms “a” or “an,” as used herein, are definedas one or more than one. Also, the use of introductory phrases such as“at least one” and “one or more” in the claims should not be construedto imply that the introduction of another claim element by theindefinite articles “a” or “an” limits any particular claim containingsuch introduced claim element to inventions containing only one suchelement, even when the same claim includes the introductory phrases “oneor more” or “at least one” and indefinite articles such as “a” or “an.”The same holds true for the use of definite articles. Unless statedotherwise, terms such as “first” and “second” are used to distinguishbetween the elements such terms describe. Thus, these terms are notnecessarily intended to indicate temporal or other prioritization ofsuch elements. The mere fact that certain measures are recited inmutually different claims does not indicate that a combination of thesemeasures cannot be used to advantage.

While certain features of the invention have been illustrated anddescribed herein, many modifications, substitutions, changes, andequivalents will now occur to those of ordinary skill in the art. It is,therefore, to be understood that the appended claims are intended tocover all such modifications and changes as fall within the true spiritof the invention.

We claim:
 1. A cementing stage collar, comprising: a body that comprisesa flow port; a group of sleeves that comprises at least one sleeve;wherein the group of sleeves comprises exit ports; wherein the group ofsleeves is configured to move within the body thereby selectivelyblocking the flow port and selectively exposing the flow port to aninterior of the cementing stage collar; wherein at least one sleeve isdissolvable; and a first closing element that is configured to receive asealing element and to seal the cementing stage collar; wherein thefirst closing element is dissolvable.
 2. The cementing stage collaraccording to claim 1 wherein the first closing element is a closingseat.
 3. The cementing stage collar according to claim 2, wherein theclosing seat comprises a removable and non-solvable cover that covers adissolvable portion of the closing seat.
 4. The cementing stage collaraccording to claim 1 wherein at least a part of the group of sleeves aredissolvable.
 5. The cementing stage collar according to claim 1,comprising a stopper that is configured to seal a through port of thegroup of sleeves thereby preventing fluid to exit downstream of thecementing stage collar when the flow port is exposed to the interior ofthe cementing stage collar.
 6. The cementing stage collar according toclaim 5, wherein the stopper is dissolvable.
 7. The cementing stagecollar according to claim 1, wherein the group of sleeves comprises anopening sleeve and a closing sleeve.
 8. The cementing stage collaraccording to claim 7, wherein the opening sleeve comprises a removablenon-solvable cover that covers a dissolvable portion of the openingsleeve.
 9. The cementing stage collar according to claim 7 wherein theclosing sleeve is configured to selectively block the flow port; andwherein the opening sleeve is configured to electively expose the flowport to an interior of the opening sleeve.
 10. A method for cementing anannulus, the method comprising: feeding cement to an interior of acementing stage collar; outputting the cement from a flow port of a bodyof the cementing stage collar to the annulus while preventing the cementfrom propagating downstream to the cementing stage collar; sending asealing element to a first closing element of the cementing stagecollar; forming a seal by receiving, by the first closing element, thesealing element; wherein the first closing element is dissolvable; anddissolving parts of the cementing stage collar; wherein the partscomprises the first closing element, thereby opening a downstream fluidpath that passes through the cementing stage collar.